A good compromise would be to open the item in a modal/sidebar/slideover by default and have a pop-out ↗ link to move to a seperate page. Jira does this for example.<p>This retains the benefits related to browser navigation while allowing quick inspection without loss of context.<p>It's also easy to implement in any decent front-end framework.
<i>"if you need to support older browsers"</i><p>Cute, but I'm pretty sure that era is over. I found out the other day that Logitech's website is unusable on the default Win7 browser.